Asymptomatic carriage of group A streptococcus is associated with elimination of capsule production.

ABSTRACT: Humans commonly carry pathogenic bacteria asymptomatically, but despite decades of study, the underlying molecular contributors remain poorly understood. Here, we show that a group A streptococcus carriage strain contains a frameshift mutation in the hasA gene resulting in loss of hyaluronic acid capsule biosynthesis. This mutation was repaired by allelic replacement, resulting in restoration of capsule production in the isogenic derivative strain. The "repaired" isogenic strain was significantly more virulent than the carriage strain in a mouse model of necrotizing fasciitis and had enhanced growth ex vivo in human blood. Importantly, the repaired isogenic strain colonized the mouse oropharynx with significantly greater bacterial burden and had significantly reduced ability to internalize

SUBMITTER: Flores AR 

PROVIDER: S-EPMC4187823 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature